Pycnogonum litorale is a marine arthropod in the family Pycnogonidae, the sea spiders.

Pycnogonum litorale has a head, a small slender prosome (thorax) and a tiny opisthosome (abdomen), the trunk being up to 1 cm (0.4 in) in length.

It is also present in the northwestern Atlantic, ranging from the Gulf of St. Lawrence southwards to New York State.

The proboscis is inserted into the prey and some body fluid is sucked out; the sea spider can be considered a parasite rather than a predator, as the food source is not killed; sea anemones that are targeted include Actinia equina, Anemonia viridis, Calliactis parasitica and Metridium dianthus.

The process is initiated by the male clinging to the female above her head, which stimulates her to expel her eggs from orifices at the base of her legs.